原标题：7月24日 GMAT数学逻辑每日一练

GMAT数学逻辑每日一练

【数学】

A collection of 36 cards consists of 4 sets of 9 cardseach. The 9 cards in each set arenumbered 1 through 9. If one card hasbeen removed from the collection, what is the number on that card?

(1) The units digit of the sumof the numbers on the remaining 35 cards is 6.

(2) The sum of the numbers onthe remaining 35 cards is 176.

A. Statement (1) ALONEis sufficient, but statement(2) alone is not sufficient.

B. Statement (2) ALONEis sufficient, but statement(1) alone is not sufficient.

C. BOTH statements TOGETHERare sufficient,but NEITHERstatement ALONEis sufficient.

D. EACHstatement ALONEis sufficient.

E. Statements (1) and (2) TOGETHERare NOTsufficient.

【逻辑】

In a new police program, automobile owners in someneighborhoods whose cars are not normally driven between 1 A.M. and 5 A.M. candisplay a special decal in the cars’ windows and authorize police to stop thecars during those hours to check the drivers’ licenses. The theft rate for carsbearing such decals is much lower than had been usual for cars in those neighborhoods.

If it is concluded from the statements above that automobiletheft has been reduced by the program, which one of the following would be mostimportant to answer in evaluating that conclusion?

A. Are owners whoare cautious enough to join the program taking other special measures toprotect their cars against theft?

B. In how manyneighborhoods is the police program operating?

C. Are cars inneighborhoods that are actively participating in the program sometimes stolenduring daylight hours?

D. Will owners whohave placed decals on their cars’ windows but who find it necessary to drivebetween 1 A.M. and 5 A. M. Be harassed by police?

E. Are theneighborhoods in which the program has been put into effect a representativecross section of neighborhoods with respect to the types of automobiles ownedby residents?

答案

【数学】

参考答案：D

题目翻译：四套牌，都是1-9.拿走一张，是多少？

题目全解：

(1) 剩下的牌，总和个位是6. 不拿走总和是180，牌都是1-9，所以拿走了4；SUFFICIENT；

(2) 剩下拍总和176，拿走的是4；SUFFICIENT。

【逻辑】

参考答案:A

思路：In my view, the reasoning in this argument is that:

automobile owners in some neighborhoods whose cars are notnormally driven between 1 A.M. and 5 A.M. can display a special decal in thecars’ windows and authorize police to stop the cars during those hours to checkthe drivers’ licenses The theft rate for cars bearing such decals is muchlower than had been usual for cars in those neighborhoods

The hidden assumption is that the decrease in the theft ratefor cars bearing such decals is due to the program.

Which is the best choice to evaluate the conclusion? Itseems to me that the correct statement can either support or weaken theargument. That is to say, the answer is the two-side sword to the argument.

After this analysis, we can find that A is just choice.

If owners who are cautious enough to join the program takingother special measures to protect their cars against theft, A will weaken theargument. If not, A obviously support the argument.

Hence, A is the answer.

B is out of scope. The number of neighborhoods who is thepolice program operating is not mentioned in this argument.

C is out of scope too. Whether cars in neighborhoods thatare actively participating in the program sometimes stolen during daylighthours has no influence in evaluating this conclusion.

D is false. If so , the answer may opposite the main presumein this argument.

E is out of scope.